Internal model control based PID tuning using first-order filter

The selection of filter plays an important role in internal model control (IMC) based controller design. As per the rule, for a minimum-phase delay free plant, IMC based controller is obtained by augmenting a filter. We suggest the use of first-order filter for controller design, which is then parameterized to a conventional PID controller. The proposed scheme brings filter size reduction, closed-loop bandwidth enhancement, and easy formulation of the PID structure. The proposed scheme is applied to some class of linear and nonlinear processes. Further the hardware testing for velocity control of precision modular servo system which contains DC servomotor is carried out through this scheme. Quantitative comparison of servo, regulatory and optimal attributes of the proposed scheme with other popular IMC-PID control techniques depicts sharp reference tracking, good disturbance rejection and minimum integral error performance.